Ohm's Law Application

The following shows a 4.0 Ω resistor and an 8.0 Ω resistor connected to a 6.0 V battery. What is the current in the battery?

• 0.5 A

• 0.75 A

• 1. 1.5 A

• 2.0 A

Answer explanation

The total resistance in the circuit is 4.0 Ω + 8.0 Ω = 12.0 Ω. Using Ohm's Law (V = IR), the current (I) = V / R = 6.0 V / 12.0 Ω = 0.5 A. Therefore, the correct answer is 0.5 A.

The following shows a 4.0 W and an 8.0 W resistor connected to a 6.0 V battery. What is the effective resistance?

• 8 ohm

• 0.375 ohm

• 4 ohm

• 2.67 ohm

Answer explanation

To find the effective resistance, use the formula 1/Reff = 1/R1 + 1/R2. Plugging in the values, Reff = 1/(1/4 + 1/8) = 2.67 ohm.

The following shows a 4.0 W and an 8.0 W resistor connected to a 6.0 V battery. What is the current in the 8 ohm resistor?

• 0 A

• 0.50 A

• 0.75 A

• 1.0 A

Answer explanation

The current in the 8 ohm resistor can be calculated using Ohm's Law: I = V / R. Therefore, I = 6.0 V / 8.0 ohm = 0.75 A. Hence, the correct answer is 0.75 A.

Identical resistors are connected to form arrangements X, Y and Z. What is the correct order of the resistances of the circuits from the largest to the smallest?

• X > Y >  Z

• Y >  X > Z

• Z > X > Y

• Z > Y > X

Answer explanation

The correct order of resistances is Z > X > Y because the circuit with Z arrangement will have the highest total resistance due to the series connection of identical resistors.

40 lamps, each of resistance 8.0 Ω, are connected in series to a 240 V supply to decorate a tree. Calculate the total resistance (ohm) of all the lamp.

40 lamps, each of resistance 8.0 Ω, are connected in series to a 240 V supply to decorate a tree. Calculate the potential difference (V) across each lamp.

40 lamps, each of resistance 8.0 Ω, are connected in series to a 240 V supply to decorate a tree. Calculate the current (A) in each lamp.